Apparatus for performing well work on floating platform

ABSTRACT

An apparatus for supporting a well intervention device connected to a well extending from a floating platform. The apparatus comprises a frame assembly having a first and second end, and wherein the first end is positioned on the platform. The apparatus includes a crown assembly attached to the second end of the frame assembly, a motion compensator member attached to the frame assembly for compensating for vertical movements of the platform, and a travel head having a first connector and a second connector, and wherein the first connector is attached to the compensator member and the second connector attaches the travel head to the well intervention device.

BACKGROUND OF THE INVENTION

This invention relates to an apparatus for performing well work on afloating platform. More particularly, but not by way of limitation, thisinvention relates to an apparatus for performing well work including aframe assembly with travel head and a method of use on a floatingplatform.

In the search for hydrocarbons, operators find it necessary to drill andcomplete wells in exotic locations. For instance, wells are beingdrilled in oceans wherein the water depth may be several thousand feet.As those of ordinary skill in the art will recognize, the wells aredrilled from rigs that are floating on the ocean surface. Once drilled,the wells are completed, and production facilities are installed. Duringthe course of drilling, completing and producing, numerous wellintervention techniques must be employed. However, in the case ofoffshore wells, operational problems arise with the floating platforms,including but not limited to the currents, tides, winds and wavescreating a constantly changing ocean surface. Hence, the normal movementof the ocean surface causes drilling, completing, and producing problemsin these offshore environments.

One of the common problems encountered by floating offshore platforms isthat the floating structure rises and lowers with the oscillation of theocean surface. In many instances, a well extends from the sub-sea, andwherein the well will be connected to the platform via a marine riser.However, this can create significant stresses in the event that thefloating platform (or some appurtenance to the platform) is attached tothe well (and/or marine riser) since the floating platform rises andlowers with the ocean surface.

Therefore, there is a need for a device that will allow for wellintervention work on offshore floating platforms. There is also a needfor a system that will permit a frame assembly to be rigged up onfloating platforms and allow for motion compensation while well work isongoing. There is a further need for a frame assembly with a travel headthat can aid in performing well work on floating platforms, includingvessels. These, and many other needs, will be met by the inventionherein described.

SUMMARY OF THE INVENTION

An apparatus for supporting a well intervention device connected to awell extending from a floating platform is disclosed. The apparatuscomprises a frame assembly having a first end and a second end, whereinthe first end is positioned on the platform, and a crown sectionassembly attached to the second end of the frame assembly. The apparatusfurther includes a motion compensator means, attached to the frameassembly, for compensating for vertical movements of the platform andmeans for supplying a power medium to the motion compensator means. Theapparatus further comprises a travel head having a first connector and asecond connector, and wherein the first connector is operativelyattached to the motion compensator means and the second connector isattached to the well intervention device.

In one preferred embodiment, the motion compensator means is operativelyattached to the first connector with the tension line leading from themotion compensator means and wherein the crown section assembly containsa sheave that has placed therein a tension line leading from the motioncompensator means and connected to the travel head.

The motion compensator means, in one preferred embodiment comprises afirst motion compensator on a first side of the frame assembly; and, asecond motion compensator on a second side of the frame assembly. Themotion compensator includes a cylinder having a piston disposed therein,with the piston being responsive to the power medium.

As the platform rises, the piston retracts into the cylinder therebykeeping the travel head in the same position; and, as the platformlowers, the piston extends from the cylinder thereby keeping the travelhead in the same position.

The frame assembly, in the most preferred embodiment, includes aplurality of frames, and wherein the plurality of frames are stackablein an array. In a preferred embodiment, the travel head includes ananchor line extending therefrom and wherein the anchor line is attachedto the ocean floor.

In one preferred embodiment, a first well intervention device isattached to a first well and a second well intervention device isattached to a second well, and wherein the travel head is fixedlyattached to the first and second well intervention device.

Additionally, the first motion compensator may include a first tensionline leading therefrom, with the first tension line being led to a firstsheave positioned in the crown section assembly; and wherein the secondmotion compensator has a second tension line leading therefrom, with thesecond tension line being lead to a second sheave positioned in thecrown section assembly.

A method for performing well intervention work on a floating platform isalso disclosed. The floating platform has a first well extending therethrough, with the first well being connected to a first wellintervention device. The method comprises providing an apparatus forsupporting the first well intervention device, the apparatus including aframe having a bottom end and a top end, wherein the bottom end ispositioned on the platform; a crown assembly attached to the top end ofthe frame; and, a cylinder, attached to the frame, with a pistonextending therefrom.

The method includes attaching a travel head, located within the frame,to a tension line extending from the cylinder, attaching the travel headto the first well intervention device, and positioning the tension linethrough a sheave, with the sheave being attached to the top end of theframe. The method further includes retracting the piston into thecylinder as the ocean and platform rises and extending the tension linewith the piston so that as the platform rises, the tension line remainsunder tension. The method further includes maintaining the travel headin a stationary position relative to the first well as the floatingplatform and frame rise with the ocean, and performing the wellintervention work with the first well intervention device while thefirst well intervention device remains in the stationary position.

As the surface of the ocean lowers, the method further compriseslowering the floating platform as the surface of the ocean lowers,extending the piston from the cylinder, contracting the tension line sothat the tension line remains in tension, and maintaining the travelhead in a stationary position relative to the well as the floatingplatform and the frame lower with the ocean.

In one preferred embodiment, the platform further contains a second welldisposed there through, and wherein the first well intervention deviceis attached to the first well and a second well intervention device isattached to the second well. The travel head is fixedly attached to thefirst and the second well intervention device and wherein the methodfurther comprises performing well intervention work on the first wellutilizing the first well intervention device and performing wellintervention work on the second well utilizing the second wellintervention device.

An advantage of the present invention includes use of the frame assemblyon a floating offshore platform. Another advantage of the presentinvention is that the frame assembly, sometimes referred to as a tower,can be used to lift and lower various tools and equipment within aworking window area of the frame assembly. The type of work includesrigging up and rigging down well intervention devices such as coiledtubing injector heads, lubricators, and blow out preventors. Anotheradvantage is that the apparatus can be simultaneously used on two wells.

A feature of the present disclosure is the motion compensator system. Inthe most preferred embodiment, two motion compensators are arranged inopposite planes relative to the frame assembly's center. Another featureis the travel head that is attached to the motion compensator system andthat is also attached to a well intervention device such as a wirelinelubricator, a coiled tubing injector head, blow out preventor, etc. Yetanother feature is that the frame, in the preferred embodiment, is madeup of various modules that are structurally stacked to a desired height.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front general layout view of the most preferred embodimentof the well intervention frame assembly of the present invention.

FIG. 1B is a side view of the frame assembly embodiment seen in FIG. 1A.

FIG. 2 is an exploded view of the frame assembly embodiment seen in FIG.1A.

FIG. 3 is an exploded view of the most preferred embodiment of the crownsection assembly.

FIG. 4 is a perspective view of the most preferred embodiment of thetravel head.

FIG. 5A is a partial cross-sectional view of a motion compensatorcylinder and piston.

FIG. 5B is the motion compensator cylinder and piston seen in FIG. 5Awith the piston disposed within the cylinder.

FIG. 6A is a schematic illustration of the system of the most preferredembodiment with the platform in a first position relative to the oceanfloor in an extended position.

FIG. 6B is a sequential schematic illustration of the system seen inFIG. 6A with the platform in a second position relative to the oceanfloor in a contracted position.

FIG. 6C is a sequential schematic illustration of the system seen inFIG. 6B with the platform in a third position relative to the oceanfloor.

FIG. 7 is a schematic illustration of the system use with dual wellintervention devices connected to dual wells.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1A, a front general layout view of the mostpreferred embodiment of the well intervention frame assembly 2 will nowbe described. In the most preferred embodiment, the frame assembly 2consist of a series of modular frames, sometimes referred to as a tower.As shown in FIG. 1A, the modular frames can be stacked one on top of theother in order to reach a specific height. FIG. 1A depicts the baseframe 4, the modular frame 6, the modular frame 8, the module frame 9,the modular frame 10, and the modular frame 12. The modules arecommercially available from Devin International Inc. under the nameTrack Stack Jr. Generally, the individual modular frames have three (3)vertical sides, and wherein one side is open in order to allow a windowfor entry (sometimes referred to as a working window area). As seen inFIG. 1A, the base frame 4 has a larger footprint (i.e. larger width) inorder to better distribute the vertical load which leads to stability ofthe frame assembly 2.

The frame assembly 2 has a first end and a second end, and wherein thefirst end (bottom end) has the template 14 that serves as the base forthe base frame 4. The second end (top end) includes the crown section16, and wherein the crown section 16 includes a rectangular frame, seengenerally at 18, and wherein a first sheave 20 is attached to therectangular frame 18 and a second sheave 22 that is attached to therectangular frame 18. The rectangular frame 18 is fixedly attached tothe modular frame 12 by conventional means, such as nuts and bolts orwelding, as well understood by those of ordinary skill in the art.

FIG. 1A also depicts the motion compensator means, attached to the frameassembly 2, for compensating for vertical movements of the platform.More specifically, a first motion compensator means 24 is attached on afirst side of the frame assembly 2 and a second motion compensator means26 is attached on a second side of the frame assembly 2. The motioncompensators will be attached via conventional means such as nuts andbolts, or welding.

The front view of FIG. 1A also depicts the window working area, seengenerally at 28. Within this working window 28 will be the travel head30 (sometimes referred to as the block) that has the first connector 32and the second connector 34. The tension line 36 is connected to theconnector 32 and is feed through the sheave 20 to the motion compensatormeans 24. The tension line 38 is connected to connector 34 and is feedthrough the sheave 22 to the motion compensator means 26. The travelhead 30 will be attached, via a connector, to a well intervention deviceas will be explained later in greater detail. The tower 2 will bepositioned on a floating platform, and wherein a subterranean well (notshown in this view) will extend from the platform. As understood bythose of ordinary skill in the art, the well intervention device will beoperatively attached to the well.

Referring now to FIG. 1B, a side view of the tower 2 seen in FIG. 1Awill now be described. It should be noted that like numbers appearing inthe various figures refer to like components. FIG. 1B depicts thestacked modular frames 6, 8, 9, 10, 12, along with the crown section 16.The travel block 30 is shown disposed within the working window 28 aspreviously described. FIG. 1B also shows a winch 45 a and line 45 b,which is attached to the template 14, and wherein the winch 45 a is usedfor rig-up, rig-down and operational purposes.

An exploded view of the tower 2 is illustrated in FIG. 2. The template14 is configured to cooperate and engage with the base frame 4. Thetemplate 14 has four sides, seen generally at 46, 48, 50, 52. FIG. 2also depicts various connecting members. The base frame 4 will havethree sides, namely sides 54, 56, 58, along with the open sidepreviously mentioned as the window working area 28. The base frame 4will be fixedly attached to the template 14. The modular frame 6 alsohas three sides, namely sides 60, 62, 64, along withe the open sidepreviously mentioned as the window working area. The modular frames 8,9, 10 and 12 are essentially identical as modular frame 6, andtherefore, their description will not be repeated. In the preferredembodiment, the template 14 is attached to the modular frame 4; themodular frame 4 is attached to the modular frame 6; the modular frame 6is attached to modular frame 8; modular frame 8 is attached to modularframe 9; modular frame 9 is attached to modular frame 10; modular frame10 is attached to modular frame 12; and modular frame 12 is attached tocrown assembly section 16. As will be appreciated by those of ordinaryskill in the art, the exact number of modular frames will be dependenton the desired height of the tower 2. Accordingly, less or more modularframes may be included.

The sheaves 20 and 22 are depicted, and wherein the tension line 36 willbe directed through sheave 20 and the tension line 38 will be directedthrough sheave 22. In turn, the tension lines 36, 38 will be connectedto the travel block 30. As seen in FIG. 2, the travel block 30 alsocontains the first connector 32 and the second connector 34. The anchorlines 40, 41 are attached to the travel block 30 at one end and at theother end to the ocean floor and a pair of working lines 42, 43 areoperatively connected to the air tuggers and are used for operational,remedial work utilizing the tower 2, such as rigging-up and rigging-downequipment.

Referring now to FIG. 3, an exploded view of the most preferredembodiment of the crown section assembly 16 will now be disclosed. Thecrown section assembly 16 includes the rectangular support frame 66, andwherein the frame 66 contains an underside 68 that will be fixedlyconnected to the modular frame 12 and a topside 70. The crown sectionassembly 16 further includes the weldment member 72 and wherein theweldment member 72 is fixedly connected to the support frame 66. Theangled braces 74, 76 are fixedly connected to the weldment member 72,and as shown, the sheave 20 is rotatably connected via bushing 78 to thebrace 74 and the sheave 22 is fixedly connected via bushing 80 to thebrace 76.

A perspective view of the most preferred embodiment of the travel head30 is illustrated in FIG. 4. The travel head 18 includes the verticalmember 84 and the vertical member 86, as well as the horizontalconnecting member 88 and the horizontal connecting member 90 are alsodepicted, and wherein the connector members can be used to connect thetravel head 30 to the well intervention device. A sheave 92 is mountedon the member 84 and a sheave 94 is mounted on the member 86. Thepurpose of sheaves 92, 94 is to connect to the anchor lines 40, 41 tothe well intervention device as well as the sea floor which in turnholds the travel head 30 stationary relative to the ocean floor.

Referring now to FIG. 5A, a partial cross-sectional view of a motioncompensator cylinder and piston, such as generally seen in FIG. 1A asnumeral 24, will now be described. In the preferred embodiment, theassembly 98 includes a cylinder 100 and a movable piston 102 disposedtherein. The piston 102 has an extended position and a contractedposition. It should be noted that a protective cage is included in oneembodiment, seen generally at 104?, and wherein the protective cage is acylindrical member that surrounds the cylinder 100 and is attached tothe frame assembly. The piston 102 will have travel cage 105 aoperatively attached thereto, and wherein the travel cage 105 a has topend eye bracket 105 b and botom end bracket 105 c. The pad eye 105 d,which is attached to the eye bracket 105 b, is attached to the tensionline. The guide cage 105 e is attached to the protective cage 104 viatop plate 105 f and bottom plate 105 g, and hence, guide cage 105 e isattached to the protective cage 104 via conventional means such aswelding. The bottom member 105 h will be attached to the platform 109 a(not seen in this view) and the protective cage 104. The contraction andextension of piston 102 will in turn cause the travel cage 105 a toextend and contract out of the protective cage 104, which in turn causespad eye 105 d to extend and contract. The tension line is connected tothe pad eye 105 d. Hence, the protective cage 104 would aid inprotecting and guarding the piston 102 and cylinder 100 from damageduring operations, as well as providing an anchoring mechanism for thecylinder 100 and piston 102 during operations.

FIG. 5B is the motion compensator cylinder and piston seen in FIG. 5Awith the piston 102 disposed within the cylinder 100. Please note thatthe motion compensator means 26 is of similar construction and will notbe repeated. The piston 102 is extended and contracted via a power packmeans, that will be described later. Note that plate 105i, with holesthere through for placement of the individual cage rods, is included toseparate the various rods of the cages during traveling movement of thepiston 102.

Referring now to FIGS. 6A, 6B, and 6C, a sequential schematicillustration of the apparatus, including the tower 2, variouscomponents, and compensation system, of the most preferred embodiment isshown with a gradually rising ocean level such that the pistons go froma extended state to a contracted state. It should be noted that a motioncompensator was described in U. S. Pat. No. 6,929,071, entitled “MotionCompensation System and Method”, assigned to Applicant, and isincorporated herein by express reference. As seen in FIG. 6A, thefloating platform 109 a contains the well intervention tower 2 alongwith the first motion compensator means 24 and the second motioncompensator means 26. The piston 102 extends from the cylinder 100. Thecylinder 100 is operatively connected to the power pack means 107 vialine 108 (which would include input and output lines as understood bythose of ordinary skill in the art) and wherein power pack means 107delivers a power medium, which in the most preferred embodiment will bea nitrogen gas, to the cylinder 100. In another embodiment, the powermedium may be a hydraulic fluid. The depth from the platform 109 a tothe ocean floor 109 b is denoted by the letter “X”

The second motion compensator means 26 contains the cylinder 110 withthe piston 112 extending therefrom. The cylinder 110 is operativelyconnected to the power pack means 107 via line 114 (which would includeinput and output lines). In the most preferred embodiment, the pistons102, 112 are connected to base frame 4 (for instance, member 105 h isconnected to the platform 109 a), and the cylinders 100, 110 (forinstance, via pad eyes 105 d) are connected to the tension lines 36, 38,respectively, as seen in FIGS. 5A and 5B. It should be noted that it ispossible to have an embodiment wherein the piston and cylinderarrangement is reversed so that the pistons are connected to the tensionlines. However, as seen in FIGS. 6A-6C, the pistons, when extendingdownward, push down on the floating platform 109 a which aids in keepingthe tension lines in tension . . . FIG. 6A represents the situationwherein the pistons have been extended . . . due to the action of thepower medium from the power pack means 107. The tension lines 36, 38connect to the travel head 30 and to the cylinders 100, 110,respectively, and wherein the tension lines 36, 38 are maintained intension in order to support the travel head 30. FIG. 6A shows the anchorline 40, 41 attaching the travel head 30 to the ocean floor 109 b.

Operators can attach well intervention devices, denoted by the numeral116 in FIGS. 6A, 6B, and 6C to the travel head 30, as previously noted.The well intervention device 116 is fixedly attached to the well 118.The operator can perform well intervention work in an oscillating sea asper the present disclosure. Well intervention devices include coiledtubing injector heads, blow out preventor stacks, and lubricators.

FIG. 6B is a simplified schematic illustration of the system seen inFIG. 6A as the surface of the ocean has risen, and wherein the depth isdenoted by the letter “Y”, and wherein the pistons are in a morecontracted position relative to FIG. 6A. Hence the pistons 102, 112 arepartially extending from the cylinders 100, 110 respectively, due to theaction of the power pack means 107 injecting nitrogen gas into thecylinders 100, 110. FIG. 6B represents the situation wherein thefloating platform has risen (due to the ocean level rising), andtherefore, the power pack means 107 causes the pistons 102, 112 topartially extend thereby pushing down on the floating platform 109 a. Atthe same time, the travel cage 105 a has extended. The tension lines areconnected to the travel cages. As previously noted, tension lines 36, 38are still maintained in tension due to the compensating effect, which inturn maintains the travel head 30 in tension and stationary.

FIG. 6C represents the sequential illustration wherein the ocean surfacehas again risen and the depth has increased to the depth denoted by theletter “Z”. As seen in FIG. 6C, the pistons 102, 112 are in a fullycontracted state . . . due to the action of the power pack means 107injecting the nitrogen gas into the cylinders 100, 110. The travel cage105 a is fully extended. The tension lines 36, 38 are still maintainedin tension due to the compensating effect, which in turn maintains thetravel head 30 in tension and stationary, as previously noted.

FIG. 7 is a schematic illustration of the frame assembly and system inuse with dual well intervention devices connected to dual wells. Morespecifically, FIG. 7 depicts the tower 2 disposed on the floatingplatform 109 a. The tension lines 36, 38 are also attached to travelcages (i.e. 105 a) of the pistons 102, 112, respectively. In thisembodiment, there are two travel heads, namely travel head 30 aindependently attached to tension line 36, and travel head 30 bindependently attached to the tension line 38. However, it is within thescope of this disclosure that in the case of dual well work, the singletravel head 30 can also be used.

FIG. 7 depicts a first well intervention device 120 attached to a firstwell 122, and a second well intervention device 124 attached to a secondwell 126. The well intervention device 120 is attached to the travelhead 30 a, and the well intervention device 124 is attached to thetravel head 30 b, as shown. Anchor lines 128, 130 from the travel heads30 a, 30 b to the sea floor are also shown.

While the particular invention as herein shown and disclosed in detailis fully capable of obtaining the features and providing the advantageshereinbefore stated, it is to be understood that this disclosure ismerely illustrative of the presently preferred embodiments of theinvention and that no limitations are intended other than as describedin the appended claims.

1. An apparatus for supporting a well intervention device connected to awell extending from a floating platform, the apparatus comprising: aframe assembly having a first end and a second end, wherein said firstend is positioned on the platform; a crown section assembly attached tothe second end of said frame assembly; a motion compensator means,attached to said frame assembly, for compensating for vertical movementsof the platform; a travel head having a first connector and a secondconnector, and wherein said first connector is attached to saidcompensator means and said second connector attaches said travel head tothe well intervention device.
 2. The apparatus of claim 1 wherein saidmotion compensator means comprises: a first motion compensator on afirst side of said frame assembly; a second motion compensator on asecond side of said frame assembly; power pack means for suppling apower medium to said first and said second motion compensator.
 3. Theapparatus of claim 1 wherein said motion compensator means comprises: acylinder having a piston disposed therein; power pack means forsupplying a power medium to said cylinder and wherein said piston isresponsive to said power medium.
 4. The apparatus of claim 1 whereinsaid motion compensator means includes a tension line extendingtherefrom and wherein said tension line is connected to said travelhead.
 5. The apparatus of claim 4 wherein said crown section assemblycontains a sheave that has placed therein said tension line.
 6. Theapparatus of claim 1 wherein said motion compensator means comprises acylinder having a piston disposed therein and wherein as said platformraises, said piston retracts into said cylinder thereby keeping saidtravel head in the same position and as said platform lowers, saidpiston extends from said cylinder thereby keeping said travel headstationary relative to the well intervention device.
 7. The apparatus ofclaim 6 wherein said frame assembly includes a plurality of frames, andwherein said plurality of frames are stackable in an array to a desiredheight.
 8. The apparatus of claim 7 wherein the well intervention deviceincludes a first well intervention device that is attached to a firstwell and a second well intervention device that is attached to a secondwell, and wherein said travel head is fixedly attached to said first andsaid second well intervention device so that the well intervention workcan be performed.
 9. An apparatus for supporting a first wellintervention device connected to a well extending from a floatingplatform comprising: a frame assembly having a first end and a secondend, wherein said first end is positioned on the platform; a crownsection assembly attached to the second end of said frame assembly; amotion compensator member, attached to said frame assembly, forcompensating for vertical movements of the platform; means for supplyinga power medium to said motion compensator member; a travel head having afirst connector and a second connector, and wherein said first connectoris operatively attached to said motion compensator member and saidsecond connector is attached to the first well intervention device. 10.The apparatus of claim 9 wherein said motion compensator member isoperatively attached to said first connector with a tension line leadingfrom said motion compensator member and wherein said crown sectionassembly contains a sheave that has placed therein said tension lineleading from said motion compensator member and connected to said travelhead.
 11. The apparatus of claim 9 wherein said motion compensatormember comprises: a first motion compensator on a first side of saidframe assembly; and, a second motion compensator on a second side ofsaid frame assembly.
 12. The apparatus of claim 10 wherein said motioncompensator member comprises: a cylinder having a piston disposedtherein, said piston being responsive to the power medium.
 13. Theapparatus of claim 12 wherein said travel head includes an anchor lineextending therefrom and wherein said anchor line is attached to theocean floor.
 14. The apparatus of claim 13 wherein as said platformraises, said piston retracts into said cylinder thereby keeping saidtravel head in the same position and as said platform lowers, saidpiston extends from said cylinder thereby keeping said travel head inthe same position.
 15. The apparatus of claim 14 wherein said frameassembly includes a plurality of frames, and wherein said plurality offrames are stackable in an array.
 16. The apparatus of claim 15 whereinsaid first well intervention device is attached to a first well and asecond well intervention device is attached to a second well, andwherein said travel head is fixedly attached to said first and saidsecond well intervention device.
 17. The apparatus of claim 11 whereinsaid first motion compensator has a first tension line leadingtherefrom, said first tension line being led to a first sheavepositioned in said crown section assembly; and wherein said secondmotion compensator has a second tension line leading therefrom, saidsecond tension line being lead to a second sheave positioned in saidcrown section assembly.
 18. A method for performing well interventionwork on a floating platform, the floating platform having a first wellextending there through, with the first well being connected to a firstwell intervention device, the method comprising: providing an apparatusfor supporting the first well intervention device, the apparatusincluding a frame having a bottom end and a top end, wherein said bottomend is positioned on the platform; a crown assembly attached to the topend of said frame; a cylinder, attached to said frame, with a pistonextending therefrom; attaching a travel head, located within said frame,to a tension line extending from the cylinder; attaching the travel headto the first well intervention device; positioning said tension linethrough a sheave, said sheave being attached to the crown assembly;retracting said piston into said cylinder as the ocean and platformrises; extending said tension line with said piston so that as saidplatform rises, the tension line remains under tension; maintaining saidtravel head in a stationary position relative to the first well as thefloating platform and the frame rise with the ocean; performing the wellintervention work with the first well intervention device while thefirst well intervention device remains in the stationary position. 19.The method of claim 18 wherein the surface of the ocean lowers and themethod further comprises: lowering the floating platform as the surfaceof the ocean lowers; extending said piston from said cylinder;contracting said tension line so that the tension line remains intension; maintaining said travel head in a stationary position relativeto the well as the floating platform and the frame lower with the ocean.20. The method of claim 19 wherein said platform further contains asecond well disposed there through, and a second well interventiondevice is attached to the second well and wherein said travel head isfixedly attached to the first and the second well intervention deviceand wherein the method further comprises: performing well interventionwork on the first well utilizing the first well intervention device;performing well intervention work on the second well utilizing thesecond well intervention device.